The New Mexico Tumor Registry (a population-based cancer registry participating in the National Cancer Insitute's Surveillance, Epidemiology and End Results, "SEER", Program) has identified marked differences in cancer incidence and mortality among the multicultural population of New Mexico. The American Indians and Spanish-Americans show excess cancers of gallbladder, stomach and cervix, and deficits in cancers of skin, breast, lung, colon, rectum and melanomas. This project will examine, in fine detail, the cancer experience of unique communities and sub-populations that are known to have low or very low genetic diversity. Analysis of high and low cancer rates among these homogeneous populations, even though the populations may be small, have a relatively high likelihood of providing new clues to cancer etiology. Existing records of the New Mexico Tumor Registry will be the basic source of information. Census material from the 1970 Census of the U.S. will allow computation of populations. Application of known incidence rates will then produce observed/expected ratios to be tested for significance. When found, individual case records will be examined for further information. Specific histologic types of important cancer sites will be studied.